Non-vitamin K antagonist oral anticoagulant use at doses inappropriately lower than recommended in outpatient older adults: a real-life data

Background/purpose: There has been a rapid increase in the use of non-vitamin K-antagonist oral anticoagulants (NOAC). Current guidelines recommend dose adjustments be made in accordance with certain criteria for each NOAC. This study is aimed at determining whether or not NOAC were prescribed for non-valvular atrial fibrillation (AF) in guideline-recommended doses in community-dwelling older adults.

Methods: Older adults taking NOAC for non-valvular AF presenting to a cardiology outpatient clinic for the first time were included in the study. The NOAC dose for each patient was assessed based on the recommendations of the European Society of Cardiology and were categorized as appropriate or inappropriate (low or high dose). The patients were also evaluated for demographic data, diseases, CHA2DS2-VASc score, HASBLED score, frailty and falls in the previous year.

Results: A total of 302 older adults were included in the study, with a mean age of 75.5 ± 7.5 years. One hundred eighty-four patients (60.9%) were found to be on appropriate doses of NOAC, while 109 (36.1%) were on inappropriately low doses and nine (2.98%) were on inappropriately high doses. Accordingly, 39.1% of the AF patients were found to be on inappropriate doses of NOAC, 92.4% of which were inappropriately low. A multivariate logistic regression analysis revealed that the only factor associated with inappropriate low-dose NOAC use was patient age (OR = 1.061, 95% CI = 1.009-1.116, p = 0.022).

Conclusion: Our study suggests that the inappropriate use of lower dose NOAC may emerge as a significant problem in outpatient older adults. This inappropriate practice seems to be associated with older age rather than the diseases, CHA2DS2-VASc/HASBLED scores, frailty and presence of falls.